Evaporative coolers are frequently utilized as parts of air conditioning systems in a relatively dry environment where a substantial differential exists between the wet bulb temperature and the dry bulb temperature of the air to be cooled. In operation, the relatively dry air to be cooled is placed in contact with water which evaporates into the dry air. As the water evaporates, it takes up the latent heat of evaporation from its surroundings, including the air, thereby cooling the same.
In the usual case, an evaporative cooling media is utilized. Water is trickled across the media while air is passed therethrough to promote good contact between the air and the water to provide the desired cooling effect. The air is typically propelled through the media by means of a fan or the like which may be either upstream or downstream of the media. In either event, care must be taken so that the velocity of air through the media is not so high as to entrain water in the liquid phase and introduce it into the space to be cooled along with the cool air. At the same time, higher velocities are often desirable as they enable the use of a lesser volume of evaporative media, allowing cooler size to be reduced. In any event, as a consequence, manufacturers of evaporative cooling media, in their specifications for their product, typically specify a maximum permitted air velocity as well as an effectiveness at a given velocity. Effectiveness is defined by the temperature difference between the temperature of the air stream entering the cooler and the temperature of the air stream exiting the cooler divided by the difference between the wet and dry bulb temperatures of the entering air and multiplied by 100.
In typical, commercially available direct evaporative cooling media today, air velocities are limited to a range of 700 feet per minute or less, because the employment of higher air velocities would possibly result in undesirable carry-over of liquid water in the air stream. Consequently, there is a need for an evaporative cooler that can achieve greater air velocities without creating a carry-over problem, or without reducing the evaporative cooler's effectiveness while being more compact in size.
At the same time, those skilled in the art will recognize that evaporative cooling media must be changed from time to time. Because water is evaporating from the surface of the media, any mineral content within the water will be left as a residue on the cooling media when the water evaporates. Over the passage of time, the build-up of mineral on the media will cause increasing fouling of the media and an accompanying drop in effectiveness.
Thus, it is standard practice to, at periodic intervals, change the evaporative cooling media in evaporative coolers before mineral build-up on the media becomes so great as to bring about inefficiencies in operation. Since, in the usual case, the media is contained in a housing, access must be achieved to the housing to remove and replace the media. This is not always an easily accomplished task because the media typically will be disposed between a water collection system that collects excess water that has not been evaporated in the media and a water distribution system which distributes water to the media for evaporation thereon. As a result, there is also a real need for a readily serviceable evaporative cooler.
The present invention is directed to providing one, or the other, or both of the foregoing needs.